The invention relates to an electronic method for approving a transaction, to a corresponding transaction system, to a transaction application for carrying out the method, to a mobile terminal having such a transaction application, and to a payment system comprising the transaction system in order to execute the transaction. In this manner, an electronic method is made available that is easy to handle and that can be used to approve a transaction within the scope of a business transaction between buyers and sellers, that can be used virtually without limitations in terms of location, that requires a minimum of already available technical infrastructure, and that is nevertheless secure for all parties involved. For this purpose, the mobile terminal has to have a display element, it has to be suitable to establish a wireless data connection with the transaction server, and it has to have application and e-mail capabilities.